Pain in the lower right side of the stomach should be examined by abdominal ultrasound, routine blood tests, and routine urine tests, not excepting that it is caused by acute appendicitis. The patient may also have abdominal distention or diarrhea, and in severe cases may also show fever. If the retroperitoneal ureter is involved, the patient may also have symptoms of urinary tract irritation, manifested by positive urine leukocytes and red blood cells. Appendicitis is also a common type of acute abdomen, due to the anatomical characteristics of the appendix, which is a blind end and where fecal obstruction can easily become secondary to infection. The most effective treatment is the surgical removal of the appendix, which is followed by intravenous anti-infective treatment and regular medication changes.